1988 LT250R Burnt Piston

fire0501 · 05-18-2011, 10:34 AM

Hello so I was riding my 250r without antifreeze......yeah i know It was only a short ride just to get the feel of the fron end because I just replaced all the a-arm bushings and bearings and a couple hundred feet from the house it lost power and died. I knew what happened but I almost dont care because I wanted to brind it back to stck anyway. It was at 1.50 over which was a 68.5mm bore.

My question is does anyone think this was caused solely by riding for tops maybe 5 minutes without antifreeze, or a jetting issue combined? I have only had this atv for 1 month and I have dont more work to it than I wanted to but at this point to I have to keep going. So that leads to my next question I just purchased a sock 67mm Piston Wiseco Prolite and an LA Sleeve, I am going to install the sleeve myself but my question is after installation, does the sleeve need to be bored or just honed out? Please let me know any information is welcomed and much appreciated!

LomaxRacing28 · 05-18-2011, 10:37 AM

That's a heat issue. I would bet money it due to no anti-freeze

. All of the lean burns I have seen burn holes in the top of the piston. If I remember correctly after it is sleeved you have to bore to size.

fire0501 · 05-18-2011, 10:40 AM

Thanks I thought so well Im going to change it back to stock anyway so I guess ill be buyin a jet kit also. I have a Mikuni Carb on there so its not the stock one how do I go about buying a jet kit for a certain carb?

LomaxRacing28 · 05-18-2011, 10:46 AM

Quote:

Originally Posted by fire0501

Thanks I thought so well Im going to change it back to stock anyway so I guess ill be buyin a jet kit also. I have a Mikuni Carb on there so its not the stock one how do I go about buying a jet kit for a certain carb?

Most cycle shops sell jets by the piece. What jets are you running right now?

fire0501 · 05-18-2011, 10:49 AM

You know I forget exactly what jets are in there but I will look tonight and post back on this

LomaxRacing28 · 05-18-2011, 11:01 AM

You shouldn't have to change it to much. I remember right I think we ran right around a 152 main, 35 pilot in our CR250 stock with a FMF Fatty and Power Core II. I am in Ohio. If that helps you at all.

fire0501 · 05-18-2011, 11:12 AM

yea it def helps, any info helps especially when talking about jetting thanks for the info I will keep this thread updated

Motoman991 · 05-18-2011, 12:00 PM

Why would you ride without coolant?

fire0501 · 05-18-2011, 01:11 PM

Quote:

Originally Posted by Motoman991

Why would you ride without coolant?

good question...

Does anyone know if a new sleeve needs to be bored to spec or is the sleeve made to just install a new std bore piston with just a hone?

sandman74 · 05-18-2011, 02:04 PM

think it needs to be bored to match the piston.

LomaxRacing28 · 05-18-2011, 02:49 PM

The sleeves are always smaller than the intended size. You will have to bore it out standard or otherwise. What are you using for top end oil?

fire0501 · 05-18-2011, 03:14 PM

oil for the top end? do you mean what do i mix in the gas? I like Amsoil if that what you mean

Motoman991 · 05-18-2011, 03:15 PM

The sleeve will need to be matched to the piston.

fire0501 · 05-18-2011, 03:17 PM

Cool thanks for all the replies I called the local Dealership and they will do the boring for $70.

LomaxRacing28 · 05-18-2011, 04:08 PM

Yeah that's what I meant. We run Castor927 even with our methanol application. Amsoil is good stuff. Unfortunately can't run it with methanol.

05-18-2011, 10:34 AM	#1 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	1988 LT250R Burnt Piston Hello so I was riding my 250r without antifreeze......yeah i know It was only a short ride just to get the feel of the fron end because I just replaced all the a-arm bushings and bearings and a couple hundred feet from the house it lost power and died. I knew what happened but I almost dont care because I wanted to brind it back to stck anyway. It was at 1.50 over which was a 68.5mm bore. My question is does anyone think this was caused solely by riding for tops maybe 5 minutes without antifreeze, or a jetting issue combined? I have only had this atv for 1 month and I have dont more work to it than I wanted to but at this point to I have to keep going. So that leads to my next question I just purchased a sock 67mm Piston Wiseco Prolite and an LA Sleeve, I am going to install the sleeve myself but my question is after installation, does the sleeve need to be bored or just honed out? Please let me know any information is welcomed and much appreciated! Last edited by fire0501; 06-16-2011 at 12:54 PM.

05-18-2011, 10:37 AM	#2 (permalink)
LomaxRacing28 :::Mini LT50 Rider::: Join Date: Oct 2007 Location: NE Ohio Posts: 64	That's a heat issue. I would bet money it due to no anti-freeze. All of the lean burns I have seen burn holes in the top of the piston. If I remember correctly after it is sleeved you have to bore to size. Last edited by LomaxRacing28; 05-18-2011 at 10:44 AM.

05-18-2011, 02:04 PM	#10 (permalink)
sandman74 :::Vinson Rider...wtf?::: Join Date: Jun 2009 Posts: 705	think it needs to be bored to match the piston. __________________ Trinity Stage 4 full exhaust, UNI filter w/ DIY powerlid, 400EX airboot, FCR39, R&D fuel screw, DRZe kit, Yoshimura Cams, Motion Pro Twist throttle, Pro Taper bars, YFZ calipers, TRX master cylinder, KX clutch perch, KTM lines, Acerbis hand guards, TrailTech Vapor, aluminum radiator shrouds, aluminum heal guards, bossbearing DLR conversion, ZX6 LED tail-light, full PRM skids and bumper, ITP's w/GNCC's, Laegers +2, Houser +1.25

05-18-2011, 10:40 AM	#3 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	Thanks I thought so well Im going to change it back to stock anyway so I guess ill be buyin a jet kit also. I have a Mikuni Carb on there so its not the stock one how do I go about buying a jet kit for a certain carb?

05-18-2011, 10:49 AM	#5 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	You know I forget exactly what jets are in there but I will look tonight and post back on this

05-18-2011, 11:01 AM	#6 (permalink)
LomaxRacing28 :::Mini LT50 Rider::: Join Date: Oct 2007 Location: NE Ohio Posts: 64	You shouldn't have to change it to much. I remember right I think we ran right around a 152 main, 35 pilot in our CR250 stock with a FMF Fatty and Power Core II. I am in Ohio. If that helps you at all.

05-18-2011, 11:12 AM	#7 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	yea it def helps, any info helps especially when talking about jetting thanks for the info I will keep this thread updated

05-18-2011, 12:00 PM	#8 (permalink)
Motoman991 :::Ozark 250 rider::: Join Date: Apr 2011 Location: Amelia, OH Posts: 355	Why would you ride without coolant?

05-18-2011, 02:49 PM	#11 (permalink)
LomaxRacing28 :::Mini LT50 Rider::: Join Date: Oct 2007 Location: NE Ohio Posts: 64	The sleeves are always smaller than the intended size. You will have to bore it out standard or otherwise. What are you using for top end oil?

05-18-2011, 03:14 PM	#12 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	oil for the top end? do you mean what do i mix in the gas? I like Amsoil if that what you mean

05-18-2011, 03:15 PM	#13 (permalink)
Motoman991 :::Ozark 250 rider::: Join Date: Apr 2011 Location: Amelia, OH Posts: 355	The sleeve will need to be matched to the piston.

05-18-2011, 03:17 PM	#14 (permalink)
fire0501 :::Rookie Rider::: Join Date: Mar 2011 Posts: 23	Cool thanks for all the replies I called the local Dealership and they will do the boring for $70.

05-18-2011, 04:08 PM	#15 (permalink)
LomaxRacing28 :::Mini LT50 Rider::: Join Date: Oct 2007 Location: NE Ohio Posts: 64	Yeah that's what I meant. We run Castor927 even with our methanol application. Amsoil is good stuff. Unfortunately can't run it with methanol.

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